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authorSergei Trofimovich <slyfox@gentoo.org>2021-04-29 22:55:12 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-04-30 11:20:36 -0700
commitf58bd538e6a2deb2bcdfe527d9ed45643348a4e6 (patch)
tree26ff5f7c7272bf333dc7fe452d1f7ad511dd1585 /lib
parent8e9b16c47680f6e7d6e5864a37f313f905a91cf5 (diff)
downloadlinux-f58bd538e6a2deb2bcdfe527d9ed45643348a4e6.tar.gz
mm: page_poison: print page info when corruption is caught
When page_poison detects page corruption it's useful to see who freed a page recently to have a guess where write-after-free corruption happens. After this change corruption report has extra page data. Example report from real corruption (includes only page_pwner part): pagealloc: memory corruption e00000014cd61d10: 11 00 00 00 00 00 00 00 30 1d d2 ff ff 0f 00 60 ........0......` e00000014cd61d20: b0 1d d2 ff ff 0f 00 60 90 fe 1c 00 08 00 00 20 .......`....... ... CPU: 1 PID: 220402 Comm: cc1plus Not tainted 5.12.0-rc5-00107-g9720c6f59ecf #245 Hardware name: hp server rx3600, BIOS 04.03 04/08/2008 ... Call Trace: [<a000000100015210>] show_stack+0x90/0xc0 [<a000000101163390>] dump_stack+0x150/0x1c0 [<a0000001003f1e90>] __kernel_unpoison_pages+0x410/0x440 [<a0000001003c2460>] get_page_from_freelist+0x1460/0x2ca0 [<a0000001003c6be0>] __alloc_pages_nodemask+0x3c0/0x660 [<a0000001003ed690>] alloc_pages_vma+0xb0/0x500 [<a00000010037deb0>] __handle_mm_fault+0x1230/0x1fe0 [<a00000010037ef70>] handle_mm_fault+0x310/0x4e0 [<a00000010005dc70>] ia64_do_page_fault+0x1f0/0xb80 [<a00000010000ca00>] ia64_leave_kernel+0x0/0x270 page_owner tracks the page as freed page allocated via order 0, migratetype Movable, gfp_mask 0x100dca(GFP_HIGHUSER_MOVABLE|__GFP_ZERO), pid 37, ts 8173444098740 __reset_page_owner+0x40/0x200 free_pcp_prepare+0x4d0/0x600 free_unref_page+0x20/0x1c0 __put_page+0x110/0x1a0 migrate_pages+0x16d0/0x1dc0 compact_zone+0xfc0/0x1aa0 proactive_compact_node+0xd0/0x1e0 kcompactd+0x550/0x600 kthread+0x2c0/0x2e0 call_payload+0x50/0x80 Here we can see that page was freed by page migration but something managed to write to it afterwards. [slyfox@gentoo.org: s/dump_page_owner/dump_page/, per Vlastimil] Link: https://lkml.kernel.org/r/20210407230800.1086854-1-slyfox@gentoo.org Link: https://lkml.kernel.org/r/20210404141735.2152984-1-slyfox@gentoo.org Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org> Acked-by: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib')
0 files changed, 0 insertions, 0 deletions